Definition
The 404 (Not Found) error is an HTTP status code indicating the server could not find the requested resource. It occurs when a user or bot accesses a URL that no longer exists or never existed. Too many 404 pages can negatively affect SEO by wasting crawl budget and creating a poor user experience. It is recommended to set up a custom 404 page with links to main content and redirect old URLs using 301 redirects.
Key Points
- Indicates a page does not or no longer exists on the server
- Too many 404s waste crawl budget and hurt SEO
- Set up 301 redirects and a custom 404 page
Practical Examples
Deleted page
A site deletes 50 articles without setting up redirects. All 50 URLs return 404 errors, and backlinks to these pages lose all their SEO value.
Custom 404 page
A site creates an attractive 404 page with a search engine, links to popular pages, and a humorous message, reducing the bounce rate of lost visitors.
Frequently Asked Questions
A few 404 errors are normal and do not directly penalize. But many 404s, especially on pages with backlinks, waste crawl budget and lose the value of incoming links.
Use Google Search Console (Coverage report), crawling tools like Screaming Frog, or Ahrefs to identify all URLs returning a 404.
Go Further with LemmiLink
Discover how LemmiLink can help you put these SEO concepts into practice.
Last updated: 2026-02-07